U.S. patent number 8,004,484 [Application Number 11/857,280] was granted by the patent office on 2011-08-23 for display device, light receiving method, and information processing device.
This patent grant is currently assigned to Sony Corporation. Invention is credited to Tsutomu Harada, Masafumi Matsui, Takeru Tamayama, Mitsuru Tateuchi, Go Yamanaka.
United States Patent |
8,004,484 |
Tateuchi , et al. |
August 23, 2011 |
**Please see images for:
( Certificate of Correction ) ** |
Display device, light receiving method, and information processing
device
Abstract
A display device, light receiving method, and information
processing device are provided. The display device including a
plurality of sub-pixels forming a pixel as a unit of display
resolution of an image, the plurality of sub-pixels being arranged
in a delta arrangement, a display circuit for displaying the image,
a light receiving sensor for detecting light, the display circuit
and the light receiving sensor being disposed in each of the
sub-pixels, wherein display signal lines for supplying a display
signal to the sub-pixels are wired to all of the sub-pixels in a
same direction, two or more the light receiving sensors arranged in
a direction perpendicular to the wiring direction of the display
signal lines are connected to each other, and a received light
signal obtained from the two or more the light receiving sensors
connected to each other is output from a light receiving
circuit.
Inventors: |
Tateuchi; Mitsuru (Kanagawa,
JP), Yamanaka; Go (Kanagawa, JP), Harada;
Tsutomu (Kanagawa, JP), Tamayama; Takeru
(Kanagawa, JP), Matsui; Masafumi (Kanagawa,
JP) |
Assignee: |
Sony Corporation (Tokyo,
JP)
|
Family
ID: |
39274597 |
Appl.
No.: |
11/857,280 |
Filed: |
September 18, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080084377 A1 |
Apr 10, 2008 |
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Current U.S.
Class: |
345/92 |
Current CPC
Class: |
G09G
3/3648 (20130101); G09G 2360/144 (20130101) |
Current International
Class: |
G09G
3/36 (20060101) |
Field of
Search: |
;345/173,175,87,90,92,102 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2000-010123 |
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Jan 2000 |
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JP |
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2000-19478 |
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Jan 2000 |
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JP |
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2004-127272 |
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Apr 2004 |
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JP |
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2005-031661 |
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Feb 2005 |
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JP |
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2005-284661 |
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Oct 2005 |
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JP |
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2005-293374 |
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Oct 2005 |
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JP |
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2005-530217 |
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Oct 2005 |
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JP |
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2005-327106 |
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Nov 2005 |
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JP |
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2006-013407 |
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Jan 2006 |
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JP |
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2006-127212 |
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May 2006 |
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JP |
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2006-244218 |
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Sep 2006 |
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JP |
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2006-244446 |
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Sep 2006 |
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JP |
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2005/091262 |
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Sep 2005 |
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WO |
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2006/117955 |
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Nov 2006 |
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WO |
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Primary Examiner: Hjerpe; Richard
Assistant Examiner: Parker; Jeffrey
Attorney, Agent or Firm: K&L Gates LLP
Claims
The invention is claimed as follows:
1. A display device comprising: a plurality of sub-pixels forming a
pixel as a unit of display resolution of an image, said plurality
of sub-pixels being arranged in a delta arrangement; a display
circuit for displaying said image; a light receiving sensor for
detecting light, said display circuit and said light receiving
sensor being disposed in each of said sub-pixels, wherein display
signal lines for supplying a display signal to said sub-pixels are
wired to all of said sub-pixels in a same direction, two or more
said light receiving sensors arranged in a direction perpendicular
to the wiring direction of said display signal lines are connected
to each other, and a received light signal obtained from the two or
more said light receiving sensors connected to each other is output
from a light receiving circuit, wherein the light receiving circuit
includes at least two types of subordinate light receiving circuits
disposed in different sub-pixels of a same pixel, wherein only one
type of subordinate light receiving circuit includes an
amplifier.
2. The display device as claimed in claim 1, wherein a received
light signal line to which said received light signal is output is
wired in a same direction as the wiring direction of said display
signal lines.
3. The display device as claimed in claim 1, wherein said display
circuit controls transmittance for light from a backlight by a
liquid crystal layer.
4. The display device as claimed in claim 1, wherein said light
receiving sensor is one of a TFT as Thin Film Transistor and a
diode.
5. The display device as claimed in claim 1, wherein said display
circuit controls a self-luminous element.
6. The display device as claimed in claim 1, wherein said
sub-pixels include sub-pixels of R as Red, G as Green, and B as
Blue.
7. A light receiving method of a display device, said display
device having a plurality of sub-pixels forming a pixel as a unit
of display resolution of an image, said plurality of sub-pixels
being arranged in a delta arrangement, a display circuit for
displaying said image and a light receiving sensor for detecting
light, said display circuit and said light receiving sensor being
disposed in each of said sub-pixels, display signal lines for
supplying a display signal to said sub-pixels, said display signal
lines being wired to all of said sub-pixels in a same direction,
and a light receiving circuit including at least two types of
subordinate light receiving circuits disposed in different
sub-pixels of a same pixel, wherein only one type of subordinate
light receiving circuit includes an amplifier, said light receiving
method comprising: outputting a received light signal obtained from
two or more of said light receiving sensors arranged in a direction
perpendicular to the wiring direction of said display signal
lines.
8. The light receiving method as claimed in claim 7, wherein a
received light signal line to which said received light signal is
output is wired in a same direction as the wiring direction of said
display signal lines.
9. The light receiving method as claimed in claim 7, wherein said
display circuit controls transmittance for light from a backlight
by a liquid crystal layer.
10. The light receiving method as claimed in claim 7, wherein said
light receiving sensor is one of a TFT as Thin Film Transistor and
a diode.
11. The light receiving method as claimed in claim 7, wherein said
display circuit controls a self-luminous element.
12. The light receiving method as claimed in claim 7, wherein said
sub-pixels include sub-pixels of R as Red, G as Green, and B as
Blue.
13. An information processing device comprising: displaying and
light receiving means for displaying predetermined information as
an image and detecting light by a light receiving sensor; input
information analyzing means for analyzing externally input
information, using a received light image generated from a received
light signal output by said light receiving sensor; and controlling
means for performing a predetermined controlling process in
correspondence with a message supplied from said input information
analyzing means; wherein in said displaying and light receiving
means, a plurality of sub-pixels forming a pixel as a unit of
display resolution of said image are arranged in a delta
arrangement, a display circuit for displaying said image and said
light receiving sensor are disposed in each of said sub-pixels, a
display signal line for supplying a display signal to said
sub-pixels is wired to all of said sub-pixels in a same direction,
and a light receiving circuit including at least two types of
subordinate light receiving circuits disposed in different
sub-pixels of a same pixel, wherein only one type of subordinate
light receiving circuit includes an amplifier, and said displaying
and light receiving means outputs a received light signal obtained
from two or more said light receiving sensors arranged in a
direction perpendicular to the wiring direction of said display
signal lines.
14. The information processing device as claimed in claim 13,
wherein a received light signal line to which said received light
signal is output is wired in a same direction as the wiring
direction of said display signal lines.
15. The information processing device as claimed in claim 13,
wherein said display circuit controls transmittance for light from
a backlight by a liquid crystal layer.
16. The information processing device as claimed in claim 13,
wherein said light receiving sensor is one of a TFT as Thin Film
Transistor and a diode.
17. The information processing device as claimed in claim 13,
wherein said display circuit controls a self-luminous element.
18. The information processing device as claimed in claim 13,
wherein said sub-pixels include sub-pixels of R as Red, G as Green,
and B as Blue.
19. An information processing device comprising: a displaying and
light receiving section configured to display predetermined
information as an image and detecting light by a light receiving
sensor; an input information analyzing section configured to
analyze externally input information, using a received light image
generated from a received light signal output by said light
receiving sensor; and a controlling section configured to perform a
predetermined controlling process in correspondence with a message
supplied from said input information analyzing section; wherein in
said displaying and light receiving section, a plurality of
sub-pixels forming a pixel as a unit of display resolution of said
image are arranged in a delta arrangement, a display circuit for
displaying said image and said light receiving sensor are disposed
in each of said sub-pixels, a display signal line for supplying a
display signal to said sub-pixels is wired to all of said
sub-pixels in a same direction, and a light receiving circuit
including at least two types of subordinate light receiving
circuits disposed in different sub-pixels of a same pixel, wherein
only one type of subordinate light receiving circuit includes an
amplifier, and said displaying and light receiving section outputs
a received light signal obtained from two or more said light
receiving sensors arranged in a direction perpendicular to the
wiring direction of said display signal lines.
20. The display device as claimed in claim 1, further comprising: a
first type of subordinate light receiving circuit including a first
sensor and a first switching element, and lacking an amplifier, and
a second type of subordinate light receiving circuit including a
second sensor, a second switching element, and an amplifier,
wherein a subordinate light receiving circuit of the first type is
disposed in a first sub-pixel and a subordinate light receiving
circuit of the second type is disposed in a second sub-pixel in a
same pixel as the first sub-pixel.
21. The display device as claimed in claim 1, wherein only one
subordinate light receiving circuit in the pixel includes an
amplifier, and a sum total signal output from the two or more said
light receiving sensors is input to the amplifier.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
The present application claims priority to Japanese Patent
Application JP 2006-27604 filed in the Japan Patent Office on Oct.
10, 2006, the entire contents of which being incorporated herein by
reference.
BACKGROUND
The present application relates to a display device, a light
receiving method, and an information processing device, and
particularly to a display device, a light receiving method, and an
information processing device that can improve the S/N ratio of a
received light signal with a simple configuration.
A display device that has a display circuit and a light receiving
circuit arranged on a same substrate and is thus able to display an
image and receive external light has been proposed (see for
example, Japanese Patent Laid-Open No. 2000-19478 and Japanese
Patent Laid-Open No. 2006-127212). The light receiving circuit in
the display device detects for example light emitted from an object
(for example a pen or the like) having an external light source
such as an LED (Light Emitting Diode) or the like or light as a
result of light from a backlight being reflected and returned by a
finger or a pen in contact with a screen. In Japanese Patent
Laid-Open No. 2006-127212, the present applicant proposes a method
of driving a light receiving circuit when detecting light as a
result of light from a backlight being reflected and returned by a
finger or a pen in contact with a screen.
While Japanese Patent Laid-Open No. 2000-19478 and Japanese Patent
Laid-Open No. 2006-127212 disclose techniques for a liquid crystal
display device of a type that controls liquid crystal by the
display circuit, there is also a display device that performs image
display and light reception using an organic EL
(electroluminescence) element as a self-luminous element (see for
example, Japanese Patent Laid-Open No. 2004-127272 and Japanese
Patent Laid-Open No. 2005-293374).
In a display device having a display circuit and a light receiving
circuit arranged on a same substrate as described above, when the
S/N ratio of a received light signal output by the light receiving
circuit is to be increased, the sensor size of a light receiving
sensor needs to be enlarged. However, it is difficult to simply
enlarge the sensor size of the light receiving sensor because of
physical limitations for maintaining display performance such as
securing an aperture.
SUMMARY
The present application has been made in view of such a situation,
and it is desirable to improve the S/N ratio of the received light
signal with a simple configuration.
According to an embodiment, there is provided a display device
including a plurality of sub-pixels forming a pixel as a unit of
display resolution of an image, the plurality of sub-pixels being
arranged in a delta arrangement, a display circuit for displaying
the image, a light receiving sensor for detecting light, the
display circuit and the light receiving sensor being disposed in
each of the sub-pixels, wherein display signal lines for supplying
a display signal to the sub-pixels are wired to all of the
sub-pixels in a same direction, two or more the light receiving
sensors arranged in a direction perpendicular to the wiring
direction of the display signal lines are connected to each other,
and a received light signal obtained from the two or more the light
receiving sensors connected to each other is output from a light
receiving circuit.
According to an embodiment, there is provided a light receiving
method of a display device, the display device having a plurality
of sub-pixels forming a pixel as a unit of display resolution of an
image, the plurality of sub-pixels being arranged in a delta
arrangement, a display circuit for displaying the image and a light
receiving sensor for detecting light, the display circuit and the
light receiving sensor being disposed in each of the sub-pixels,
and display signal lines for supplying a display signal to the
sub-pixels, the display signal lines being wired to all of the
sub-pixels in a same direction, the light receiving method
including: outputting a received light signal obtained from two or
more light receiving sensors arranged in a direction perpendicular
to the wiring direction of the display signal lines.
According to an embodiment, there is provided an information
processing device including: displaying and light receiving means
for displaying predetermined information as an image and detecting
light by a light receiving sensor; input information analyzing
means for analyzing externally input information such as
information input by a user, using a received light image generated
from a received light signal output by the light receiving sensor;
and controlling means for performing a predetermined controlling
process in correspondence with a message supplied from the input
information analyzing means; wherein in the displaying and light
receiving means, a plurality of sub-pixels forming a pixel as a
unit of display resolution of the image are arranged in a delta
arrangement, a display circuit for displaying the image and the
light receiving sensor are disposed in each of the sub-pixels, and
a display signal line for supplying a display signal to the
sub-pixels is wired to all of the sub-pixels in a same direction,
and the displaying and light receiving means outputs a received
light signal obtained from two or more light receiving sensors
arranged in a direction perpendicular to the wiring direction of
the display signal lines.
The subject matter of the present application can improve the S/N
ratio of the received light signal with the simple configuration
according to the embodiment.
Additional features and advantages are described herein, and will
be apparent from, the following Detailed Description and the
figures.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a diagram showing an example of configuration of an
embodiment of an information processing device;
FIG. 2 is a diagram of assistance in explaining a stripe
arrangement;
FIG. 3 is a diagram of assistance in explaining a delta
arrangement;
FIG. 4 is a diagram showing an example of an arrangement of display
circuits and light receiving circuits in related art;
FIG. 5 is a diagram showing a circuit example of a display circuit
and a light receiving circuit in a case where a display panel is
formed by an LCD (Liquid Crystal Display);
FIG. 6 is a diagram showing a circuit example of a display circuit
and a light receiving circuit in a case where a display panel is
formed by an EL display;
FIG. 7 is a diagram showing a configuration of a light receiving
circuit used in a display panel in FIG. 1;
FIG. 8 is a diagram showing relation between sensor size and the
level of an output signal;
FIG. 9 is a diagram of assistance in explaining a horizontal stripe
canceller;
FIG. 10 is a diagram of assistance in explaining reasons that it is
difficult to connect sensors SSR arranged in a vertical direction
to each other;
FIG. 11 is a diagram of assistance in explaining reasons that it is
difficult to connect sensors SSR arranged in the vertical direction
to each other;
FIG. 12 is a diagram showing an example of an arrangement of a
light receiving circuit in the display panel in FIG. 1;
FIG. 13 is a diagram showing a display panel in which sub-pixels
shown in FIG. 12 are arranged in the form of a matrix;
FIG. 14 is a diagram showing another example of arrangement of
light receiving circuits in the display panel in FIG. 1; and
FIG. 15 is a flowchart of assistance in explaining a light
receiving process by the light receiving circuit of FIG. 7.
DETAILED DESCRIPTION
Preferred embodiments will hereinafter be described.
A display device according to an embodiment is a display device
(for example a display panel 25 in FIG. 1) having a plurality of
sub-pixels forming a pixel as a unit of display resolution of an
image, the plurality of sub-pixels being arranged in a delta
arrangement, and a display circuit (for example a display circuit
41 in FIG. 4) for displaying the image and a light receiving sensor
(for example a sensor SSR in FIG. 7) for detecting light, the
display circuit and the light receiving sensor being disposed in
each of the sub-pixels (for example sub-pixels SubPix in FIG. 7),
wherein display signal lines (for example display signal lines 51
in FIG. 12) for supplying a display signal to the sub-pixels are
wired to all of the sub-pixels in a same direction; and two or more
light receiving sensors (for example subordinate light receiving
circuits 101a to 101c in FIG. 12) arranged in a direction
perpendicular to the wiring direction of the display signal lines
are connected to each other, whereby a light receiving circuit (for
example a light receiving circuit 101 in FIG. 12) for outputting a
received light signal obtained from the two or more light receiving
sensors connected to each other is provided.
An information processing device according to an embodiment
includes: displaying and light receiving means (for example a
display panel 25 in FIG. 1) for displaying predetermined
information as an image and detecting light by a light receiving
sensor; input information analyzing means (for example an input
information analyzing unit 27 in FIG. 1) for analyzing externally
input information such as information input by a user, using a
received light image generated from a received light signal output
by the light receiving sensor; and controlling means (for example a
controlling unit 11 in FIG. 1) for performing a predetermined
controlling process in correspondence with a message supplied from
the input information analyzing means; wherein in the displaying
and light receiving means, a plurality of sub-pixels forming a
pixel as a unit of display resolution of an image are arranged in a
delta arrangement, a display circuit for displaying the image and
the light receiving sensor are disposed in each of the sub-pixels,
and a display signal line for supplying a display signal to the
sub-pixels is wired to all of the sub-pixels in a same direction,
and the displaying and light receiving means outputs a received
light signal obtained from two or more light receiving sensors
arranged in a direction perpendicular to the wiring direction of
the display signal lines.
Preferred embodiments of the present application will hereinafter
be described with reference to the drawings.
FIG. 1 shows an example of configuration of an embodiment of an
information processing device to which the present application is
applied.
An information processing device 1 of FIG. 1 is a portable
telephone, a digital still camera, a PDA (Personal Digital
Assistant) or the like that has at least a display device
displaying predetermined information as an image and performs
predetermined information processing such as call processing, image
pickup processing, data transmission and reception processing, and
the like. The information processing device 1 allows predetermined
information to be input by specifying a position on a screen of the
display device by a finger, a pen or the like.
The information processing device 1 includes a controlling unit 11,
a ROM 12, a communicating unit 13, a display processing unit 14,
and the like. The display processing unit 14 corresponds to the
above-described display device. The display processing unit 14
includes an image signal generating unit 21, a controller 22, a
gate driver 23, a source driver 24, a display panel 25, a received
light signal processing unit 26, an input information analyzing
unit 27, and a storing unit 28.
The controlling unit 11 controls the operation of the whole of the
information processing device 1 on the basis of a controlling
program stored in the ROM (Read Only Memory) 12. For example, the
controlling unit 11 supplies display data to be displayed on the
display panel 25 to the image signal generating unit 21 on the
basis of a command from another module not shown in the figure or
data received by the communicating unit 13. In addition, as will be
described later, the controlling unit 11 updates the display data
supplied to the image signal generating unit 21 or supplies data to
the communicating unit 13 or another module in response to a
message supplied from the input information analyzing unit 27.
Another module in this case is for example a module performing a
call function when the information processing device 1 is a
portable telephone, or a module performing an image pickup function
when the information processing device 1 is a digital still camera.
The communicating unit 13 communicates with various devices via a
network such as the Internet or the like by wire or by radio, and
supplies obtained data to the controlling unit 11. Incidentally,
when the information processing device 1 does not need to
communicate with the outside, the communicating unit 13 can be
omitted.
The image signal generating unit 21 generates an image signal for
displaying an image corresponding to the display data supplied from
the controlling unit 11. The image signal generating unit 21
outputs the generated image signal to the controller 22, which
controls the driving of the display panel 25.
The controller 22 controls the driving of the gate driver 23, which
controls the turning on (conduction) or off (non-conduction) of a
switching element disposed in each pixel of the display panel 25,
and the driving of the source driver 24, which supplies a voltage
signal (hereinafter referred to as a display signal) corresponding
to the image signal to each pixel in such a manner as to be
interlocked with the driving of the gate driver 23.
The display panel 25 is for example an LCD (Liquid Crystal Display)
in which m.times.n pixels with m pixels in a horizontal direction
and n pixels in a vertical direction are arranged in the form of a
matrix. The display panel 25 changes transmittance for light from a
backlight not shown in the figure by a liquid crystal layer,
thereby displaying predetermined information as an image. In
addition, the display panel 25 includes a light receiving sensor to
receive returned light resulting from the light from the backlight
being reflected and returned by a finger, a pen or the like in
contact with or adjacent to a surface in an uppermost part of the
display panel 25. The display panel 25 supplies a received light
signal obtained as a result of receiving the returned light to the
received light signal processing unit 26. Thus, the display panel
25 includes a display circuit for displaying an image and a light
receiving circuit for detecting light as input information.
Incidentally, one pixel as a unit of display resolution (image
display unit) is formed by three pixels of R (Red), G (Green), and
B (Blue). Therefore, to be exact, the number of all pixels forming
the display panel 25 is 3 m.times.n. Hereinafter, a pixel as a unit
of display resolution formed by three pixels of R, G, and B will be
referred to as a pixel, and each of pixels of R, G, and B forming a
pixel will be referred to as a sub-pixel.
An arrangement of the pixels of the display device is typified by a
stripe arrangement and a delta arrangement. In the display panel
25, the pixels are arranged in the delta arrangement.
The stripe arrangement and the delta arrangement are similar to
each other in that sub-pixels of R, G, and B are arranged in order
in a horizontal direction. However, the stripe arrangement and the
delta arrangement are different from each other in that, as shown
in FIG. 2, the positions of sub-pixels of the respective colors are
the same between an Nth line and an (N+1)th line in a vertical
direction in the stripe arrangement, whereas as shown in FIG. 3,
the positions of sub-pixels of the respective colors are shifted
from each other by a length L between the Nth line and the (N+1)th
line in the vertical direction in the delta arrangement. The length
L in this case is 1.5 times the width d of a sub-pixel.
The stripe arrangement is often employed by the display devices of
personal computers and portable telephones that use data and text
display heavily, while the delta arrangement is often employed by
the display devices of camcorders, digital still cameras and the
like as devices displaying natural images.
Returning to FIG. 1, the received light signal processing unit 26
subjects the received light signal supplied from the display panel
25 to predetermined amplification processing, filter processing,
image processing or the like. The received light signal processing
unit 26 then supplies the received light signal shaped after the
processing to the input information analyzing unit 27.
The input information analyzing unit 27 analyzes a position
(contact position) on the screen which position is specified by a
finger, a pen or the like, using a received light image generated
from the received light signal, and thereby analyzes information
input by the user. The input information analyzing unit 27 then
supplies a result of the analysis as a message to the controlling
unit 11. For example, when a received light signal of an Nth frame
is supplied from the received light signal processing unit 26 to
the input information analyzing unit 27, the input information
analyzing unit 27 compares a received light image generated from
the received light signal of the Nth frame with a received light
image of an immediately preceding frame ((N-1)th frame) stored in
the storing unit 28, and thereby calculates a difference between
the two received light images. Then, on the basis of the calculated
difference, the input information analyzing unit 27 analyzes the
movement of the contact position from the previous frame. When
there are a plurality of contact positions, the analysis is
performed for each of the plurality of contact positions. Further,
the input information analyzing unit 27 compares the movement of
the contact position with information on change of the contact
position for a predetermined past frame period which information is
stored in the storing unit 28. The input information analyzing unit
27 then determines a message relating to the detection of the
contact position which message is to be supplied to the controlling
unit 11.
Description will next be made of a display circuit and a light
receiving circuit provided in the display panel 25. However, prior
to the description, an example of arrangement of a display circuit
in related art and a light receiving circuit in related art within
a sub-pixel is shown in FIG. 4.
As shown in FIG. 4, a pixel Pix is formed by arranging sub-pixels
SubPix of R, G, and B in a horizontal direction. A display circuit
41 is disposed on an upper side in FIG. 4 within each of the
sub-pixels SubPix of R, G, and B, and a light receiving circuit 42
is disposed on a lower side in FIG. 4 within each of the sub-pixels
SubPix of R, G, and B. The display circuit 41 and the light
receiving circuit 42 are formed on a same substrate (glass
substrate).
A display signal line 51 is connected to the display circuit 41 in
each sub-pixel SubPix. A display signal is supplied from the source
driver 24 via the display signal line 51. The display circuits 41
of the sub-pixels SubPix of R, G, and B are also connected to a
same display selection line 52 extending in the horizontal
direction. The display circuits 41 of the sub-pixels SubPix of R,
G, and B are supplied with a display selection signal from the gate
driver 23 via the display selection line 52. The display circuit 41
controls light from the backlight according to the display
selection signal and the display signal.
On the other hand, a received light signal line 53 is connected to
the light receiving circuit 42 in each sub-pixel SubPix. The light
receiving circuit 42 controls light reception by a light receiving
sensor SSR (FIG. 5). The light receiving circuit 42 supplies a
light reception signal generated by the light reception by the
light receiving sensor to the received light signal processing unit
26 via the received light signal line 53.
FIG. 5 shows a circuit example of the display circuit 41 and the
light receiving circuit 42.
The display circuit 41 includes a switching element SW1, a liquid
crystal layer LC, a storage capacitor C and the like. The switching
element SW1 is formed by a TFT (Thin Film Transistor), for
example.
In the display circuit 41, the switching element SW1 turns on or
off a connection therein according to the display selection signal
supplied from the gate driver 23 via the display selection line 52.
When the switching element SW1 is on, a display signal from the
source driver 24 is supplied to the liquid crystal layer LC and the
storage capacitor C via the display signal line 51, and thus a
predetermined voltage is applied to the liquid crystal layer LC and
the storage capacitor C. In the liquid crystal layer LC, the
alignment of liquid crystal molecules changes according to the
applied voltage, and light from the backlight is emitted to a front
surface side of the display panel 25. When the switching element
SW1 is off, the voltage applied to the liquid crystal layer LC and
the storage capacitor C is retained. With sub-pixels SubPix
arranged in a row in the horizontal direction as a horizontal line,
the turning on and off of the switching element SW1 is sequentially
changed in a vertical direction for each horizontal line, that is,
line-sequential scanning is performed, whereby an image is
displayed by the display panel 25 as a whole.
The light receiving circuit 42 includes switching elements SW2 and
SW3, a sensor SSR, and an amplifier AMP. Each of the switching
elements SW2 and SW3 is formed by a TFT, for example. The sensor
SSR is for example formed by a photodiode or a TFT.
The sensor SSR receives light incident from the surface of the
display panel 25, and outputs a current signal corresponding to an
amount of the received light to the amplifier AMP. The amplifier
AMP converts the input current signal to a voltage signal,
amplifies the voltage signal, and then outputs the result as a
received light signal. The switching element SW3 turns on or off a
connection therein according to a readout control signal. When the
switching element SW3 is on, the output received light signal is
supplied to the received light signal processing unit 26 via the
received light signal line 53. The switching element SW2 turns on
or off a connection therein according to a reset control signal.
When the switching element SW2 is on, the received light signal is
reset.
The display circuit 41 and the light receiving circuit 42 formed as
described above are disposed within the sub-pixels SubPix, as shown
in FIG. 4.
Incidentally, the display panel 25 can also be realized by an EL
display using an organic or inorganic EL element, which is a
self-luminous element, in place of an LCD.
FIG. 6 shows a circuit example of a display circuit 41 in related
art and a light receiving circuit 42 in related art when the
display panel 25 is formed by an EL display. Incidentally, the
light receiving circuit 42 is the same as in FIG. 5, and therefore
description of the light receiving circuit 42 will be omitted.
The display circuit 41 includes switching elements SW1 and SW4, a
circuit group 61, and an EL element 62.
The circuit group 61 includes for example a display data writing
circuit and a threshold value variation correcting circuit. The
display data writing circuit is an I/V (current/voltage) converter
circuit for converting the display signal (voltage signal) supplied
from the switching element SW1 into a current signal. The threshold
value variation correcting circuit corrects variations of the
display signal which variations are caused by the switching element
SW1 (TFT threshold value correcting circuit).
The switching element SW1 turns on or off a connection therein
according to the display selection signal supplied from the gate
driver 23 via the display selection line 52. When the switching
element SW1 is on, a display signal from the source driver 24 is
supplied to the circuit group 61 via the display signal line 51.
The circuit group 61 subjects the input display signal to
processing such as the above-described I/V conversion and the
variation correction, and then outputs the display signal after the
processing to the switching element SW4. The switching element SW4
turns on or off a connection therein according to a light emission
control signal. When the switching element SW4 is on, the display
signal from the circuit group 61 is supplied to the EL element 62.
The EL element 62 thereby emits light.
Incidentally, each of the readout control signal, the reset signal,
and the light emission control signal described with reference to
FIG. 5 and FIG. 6 is supplied from the gate driver 23 or the source
driver 24 via a control line not shown in the figures.
The display circuits 41 in related art and the light receiving
circuits 42 in related art have been described above with reference
to FIGS. 4 to 6. Display circuits in the display panel 25 in FIG. 1
are arranged one in each sub-pixel SubPix, as with the display
circuit 41 in FIG. 4.
On the other hand, light receiving circuits in the display panel 25
in FIG. 1 are configured to output a received light signal with a
higher S/N ratio than that of the light receiving circuits 42 in
related art.
In order to further improve the S/N ratio of the received light
signal, it suffices to simply increase the size (light receiving
area) of the sensor SSR provided in each sub-pixel SubPix. However,
an increase in the size of the sensor within the sub-pixel SubPix
adversely affects display performance because of a reduction of an
aperture and the like, and is thus better not effected.
When instead of providing the display circuit and the light
receiving circuit on the same substrate, a display substrate and a
light receiving substrate are produced separately, and a laminated
structure of the display substrate and the light receiving
substrate is formed, physical limitation on increasing the size of
the sensor SSR is eliminated, but there occurs a problem of an
increase in cost.
Therefore, in the display panel 25, as shown in FIG. 7, sensors SSR
disposed in respective sub-pixels SubPix are connected in parallel
with each other on a substrate. Thereby, sensor size is effectively
increased, and thus the S/N ratio is improved.
That is, FIG. 7 shows a configuration of a light receiving circuit
101 employed in the display panel 25 of the information processing
device 1.
The light receiving circuit 101 in FIG. 7 includes three kinds of
subordinate light receiving circuits 101a to 101c and a sensor
connecting line 102 for connecting outputs of the sensors SSR of
the subordinate light receiving circuits 101a to 101c to each
other. The subordinate light receiving circuit 101a is formed by a
sensor SSR and a switching element SW2. The subordinate light
receiving circuit 101b is formed by a sensor SSR. The subordinate
light receiving circuit 101c is formed by a sensor SSR, an
amplifier AMP, and a switching element SW3.
Incidentally, an arbitrary number of subordinate light receiving
circuits 101b can be inserted between the subordinate light
receiving circuit 101a and the subordinate light receiving circuit
101c. It is also possible to omit the subordinate light receiving
circuit 101b.
While the amplifier AMP and the switching element SW3 need to be
provided in the subordinate light receiving circuit 101c, which is
connected to the received light signal line 53, the switching
element SW2 may be disposed in any of the subordinate light
receiving circuits 101a to 101c as long as the switching element
SW2 is connected to the outputs of the sensors SSR.
Incidentally, the sensor sizes of the respective sensors SSR
provided in the subordinate light receiving circuits 101a to 101c
do not need to be the same. In the present embodiment, however, for
simplicity of description, suppose that the sensor sizes of the
respective sensors SSR provided in the subordinate light receiving
circuits 101a to 101c are the same, and are the same as the size of
the sensor SSR in the light receiving circuit 42.
In the light receiving circuit 101, received light signals supplied
from the respective sensors SSR of the subordinate light receiving
circuits 101a and 101b are input to the amplifier AMP in the
subordinate light receiving circuit 101c via the sensor connecting
line 102. A received light signal output by the sensor SSR of the
subordinate light receiving circuit 101c is also input to the
amplifier AMP in the subordinate light receiving circuit 101c.
Hence, a signal input to the amplifier AMP is a sum total signal of
the received light signals output from the sensors SSR of the
subordinate light receiving circuits 101a to 101c. The amplifier
AMP converts the received light signal (current signal) input to
the amplifier AMP itself into a voltage signal, amplifies the
voltage signal, and then outputs the amplified voltage signal.
Thus, the subordinate light receiving circuit 101c outputs the
received light signals output from all of the sensors SSR of the
subordinate light receiving circuits 101a to 101c forming the light
receiving circuit 101 as the received light signal of the light
receiving circuit 101. The received light signal output from the
subordinate light receiving circuit 101c is supplied to the
received light signal processing unit 26 via the received light
signal line 53.
FIG. 8 is a diagram showing relation between sensor size and the
level of an output signal when the light receiving circuit 101 is
formed as shown in FIG. 7.
An axis of abscissas in FIG. 8 indicates the sensor size of the
sensors SSR of the light receiving circuit 101. The larger the
number of subordinate light receiving circuits 101a to 101c forming
the light receiving circuit 101, the larger the sensor size. An
axis of ordinates in FIG. 8 indicates the level of the output
signal (hereinafter referred to as output level) output by the
light receiving circuit 101.
The output signal output by the light receiving circuit 101
includes a received light signal as a signal component and a
sensor-caused noise signal and a noise signal originating from the
amplifier AMP as a noise component. When the circuit configuration
and the circuit constant of the amplifier AMP are not varied, the
noise component originating from the amplifier AMP is unchanged.
The circuit constant of the amplifier AMP is set so as to suit a
circuit (system) connected in a stage succeeding the amplifier AMP.
In the display panel 25, even when the number of subordinate light
receiving circuits 101a to 101c forming the light receiving circuit
101 is changed, the circuit of the amplifier AMP and the subsequent
circuit are not changed, and thus the circuit constant is also
unchanged. Hence, the noise component originating from the
amplifier AMP is unchanged even when the sensor size is
increased.
On the other hand, the noise component originating from the sensors
SSR, such for example as a leakage component, and the received
light signal output by the sensors SSR are both increased in level
in proportion to the sensor size. However, a rate of increase of
the noise component originating from the sensors SSR is
insignificant as compared with a rate of increase of the received
light signal, as shown in FIG. 8.
Thus, by connecting the sensors SSR in parallel with each other and
thereby effectively increasing the sensor size, it is possible to
increase the S/N ratio of the received light signal.
When a plurality of sensors SSR arranged in respective sub-pixels
SubPix are connected in parallel with each other on a substrate,
two connecting methods are considered; that is, a method of
connecting sensors SSR within respective sub-pixels SubPix arranged
in the direction of the display signal line 51, or the vertical
direction of the display panel 25, to each other, and a method of
connecting sensors SSR within respective sub-pixels SubPix arranged
in the direction of the display selection line 52, or the
horizontal direction of the display panel 25, to each other.
Because the display panel 25 in which pixels Pix are in the delta
arrangement has a wiring pattern referred to as a horizontal stripe
canceller on the substrate, it is difficult to carry out the former
connecting method, that is, connect sensors SSR arranged in the
vertical direction to each other.
Reasons that the presence of the horizontal stripe canceller makes
it difficult to connect sensors SSR arranged in the vertical
direction to each other will be described in detail with reference
to FIGS. 9 to 11.
The horizontal stripe canceller is a wiring pattern formed to
prevent a variation in luminance (horizontal stripe) occurring in
each horizontal line. In the delta arrangement, colors assigned to
display signal lines 51 disposed on both sides of a sub-pixel
SubPix in an odd-numbered horizontal line (hereinafter referred to
as an odd-numbered line) are different from colors assigned to
display signal lines 51 disposed on both sides of a sub-pixel
SubPix in an even-numbered horizontal line (hereinafter referred to
as an even-numbered line). Therefore a kind of noise entering the
sub-pixel SubPix in the odd-numbered line is different from a kind
of noise entering the sub-pixel SubPix in the even-numbered line.
As a result, a variation in luminance (horizontal stripe) occurs in
each horizontal line.
More specifically, directing attention to sub-pixels SubPix of G in
the delta arrangement shown in FIG. 9, a display signal line 51R
connected to sub-pixels SubPix of R and a display signal line 51G
connected to sub-pixels SubPix of G are disposed on both sides of a
sub-pixel SubPix of G in an odd-numbered line. On the other hand,
the display signal line 51G connected to the sub-pixels SubPix of G
and a display signal line 51B connected to sub-pixels SubPix of B
are disposed on both sides of a sub-pixel SubPix of G in an
even-numbered line.
Hence, noises affected by the display signals of R and G passing on
both sides of the sub-pixel SubPix of G in the odd-numbered line
occur in the sub-pixel SubPix of G in the odd-numbered line, while
noises affected by the display signals of G and B passing on both
sides of the sub-pixel SubPix of G in the even-numbered line occur
in the sub-pixel SubPix of G in the even-numbered line. Thus, a
kind of noise entering the sub-pixel SubPix in the odd-numbered
line is different from a kind of noise entering the sub-pixel
SubPix in the even-numbered line. Therefore horizontal stripes
occur. The horizontal stripe canceller is formed in each sub-pixel
SubPix on the substrate to prevent the horizontal stripes.
FIG. 10 shows a wiring pattern of a display circuit 41 within each
sub-pixel SubPix. FIG. 11 is a sectional view taken along a line
X-Y of FIG. 10.
As shown in FIG. 11, a storage capacitor line 112 is formed by a
first conductive film in a lowermost layer of a plurality of thin
film layers formed over a substrate 121, that is, on a side nearest
to the substrate 121. This first conductive film is also used to
form a display selection line 52 (FIG. 10).
A polycrystalline or amorphous silicon 123 as a second conductive
film is formed on an insulating film 122 formed on the storage
capacitor line 112. As shown in FIG. 10, the polycrystalline or
amorphous silicon 123, together with the storage capacitor line 112
formed in a rectangular shape, constitutes a storage capacitor
formation part 111. In addition, as shown in FIG. 10, the
polycrystalline or amorphous silicon 123 forms a horizontal stripe
canceller 113. Because the horizontal stripe canceller 113 is
formed so as to traverse a neighboring sub-pixel SubPix, there is a
fear of a decrease in the aperture ratio of the pixel. However, the
polycrystalline or amorphous silicon 123 is a transparent conductor
film, so that a decrease in the aperture ratio of the pixel can be
prevented.
The polycrystalline or amorphous silicon 123 is covered with an
insulating film 124 as shown in FIG. 11. A display signal line 51
is formed by a third conductive film on the insulating film 124.
Further, a planarizing film 125 planarizes the film surfaces of the
insulating film 124 and the display signal line 51. A transparent
electrode 126 is formed on the planarizing film 125.
Thus, the three conductive film layers are present on the substrate
121 on which the display circuit 41 is formed; that is, the first
conductive film forming the display selection line 52 and the
storage capacitor line 112, the second conductive film forming the
horizontal stripe canceller 113, and the third conductive film
forming the display signal line 51 in increasing order of distance
from the substrate 121.
Accordingly, whether a sensor connecting line 102 connecting
sensors SSR of sub-pixels SubPix in the vertical direction to each
other can be formed on the substrate 121 using the first to third
conductive films will be considered in order. Incidentally,
although the transparent electrode 126 (pixel electrode) is also a
conductive film layer, the transparent electrode 126 is an
electrode for applying an electric field for liquid crystal
alignment, and therefore not for being used as a conductive film
forming a circuit.
First, considering forming the sensor connecting line 102 using the
first conductive film forming the display selection line 52 and the
storage capacitor line 112, the display selection line 52 and the
storage capacitor line 112 traverse sub-pixels SubPix, and when the
sensor connecting line 102 is formed in the vertical direction
using the first conductive film, the sensor connecting line 102
intersects both of the display selection line 52 and the storage
capacitor line 112. Therefore it may be impossible to form the
sensor connecting line 102 using the first conductive film.
Next, also in the case of forming the sensor connecting line 102
using the second conductive film forming the horizontal stripe
canceller 113, the horizontal stripe canceller 113 traverses the
sub-pixels SubPix, and therefore it may be impossible to form the
sensor connecting line 102 in the vertical direction using the
second conductive film for the same reason.
As for the last case of forming the sensor connecting line 102
using the third conductive film forming the display signal line 51,
when the sensor connecting line 102 is formed by the third
conductive film forming the display signal line 51, a noise caused
by a signal charging the transparent electrode 126 from the display
signal line 51 via the switching element SW1 occurs in a received
light signal on the sensor connecting line 102. This invites a
degradation in quality of the received light signal. Therefore it
may be impossible to form the sensor connecting line 102 on the
substrate 121 using the third conductive film.
Thus, with the layer structure of conductive film layers in a
present situation, it is difficult to form the sensor connecting
line 102 for connecting sensors SSR arranged in the vertical
direction with each other on the substrate 121.
Therefore, in the display panel 25, sensors SSR arranged in the
horizontal direction are connected to each other. That is, the
sensors SSR of sub-pixels SubPix arranged in a direction
perpendicular to the wiring direction of the display signal line 51
(horizontal direction) are connected to each other by the sensor
connecting line 102.
FIG. 12 shows an example of arrangement of a light receiving
circuit 101 in a case where the light receiving circuit 101
includes a subordinate light receiving circuit 101a, one
subordinate light receiving circuit 101b, and a subordinate light
receiving circuit 101c, and the subordinate light receiving circuit
101a, the one subordinate light receiving circuit 101b, and the
subordinate light receiving circuit 101c are disposed in three
sub-pixels SubPix, respectively.
In FIG. 12, display signal lines 51 for supplying a display signal
to sub-pixels SubPix are wired in a same direction in all the
sub-pixels SubPix. The subordinate light receiving circuit 101a,
the subordinate light receiving circuit 101b, and the subordinate
light receiving circuit 101c are respectively disposed in the three
sub-pixels SubPix arranged in the direction perpendicular to the
display signal lines 51, that is, in the horizontal direction, and
are connected to each other by the sensor connecting line 102.
A VDD line and a GND line for supplying power to the subordinate
light receiving circuits 101a to 101c and a received light signal
line 53 for transmitting a received light signal output from the
light receiving circuit 101 to the received light signal processing
unit 26 are wired in the same direction as the display signal lines
51.
The VDD line and the GND line branch off at a right angle at the
same position in the vertical direction as the subordinate light
receiving circuits 101a to 101c to be connected to each of the
subordinate light receiving circuits 101a to 101c. The received
light signal line 53 is connected to the subordinate light
receiving circuit 101c via the sensor connecting line 102. The
subordinate light receiving circuits 101a to 101c are connected to
each other by the sensor connecting line 102.
In FIG. 12, wiring patterns formed by a same conductive film are
schematically represented by a same design. Thus, the received
light signal line 53, the VDD line, and the GND line are formed on
the substrate 121 by the third conductive film, which is the same
as that of the display signal lines 51. However, at positions where
the VDD line and the GND line arranged in the horizontal direction
intersect the display signal lines 51 arranged in the vertical
direction, the VDD line and the GND line are formed by the same
first conductive film as the display selection line 52 and the
storage capacitor line 112, as shown in FIG. 12. The sensor
connecting line 102 connecting the subordinate light receiving
circuits 101a to 101c to each other is formed by the same second
conductive film as the horizontal stripe canceller 113.
Thus, to connect the subordinate light receiving circuits 101a to
101c to each other does not need the addition of a new conductive
film layer. In addition, because the sensor connecting line 102 is
formed on the substrate by the conductive film different from that
of the display signal lines 51, noise caused by a display signal
does not occur in the sensor connecting line 102.
FIG. 13 is a diagram showing an arrangement of light receiving
circuits 101 of FIG. 12 in two lines, that is, an odd-numbered line
and an even-numbered line.
A side from which the output of a sensor SSR is extracted within
each sub-pixel SubPix is the same as a side where a display signal
line 51 for the sub-pixel SubPix is disposed. That is, in the
odd-numbered line, a display signal line 51 for transmitting a
display signal for a sub-pixel SubPix is disposed on the right side
of the sub-pixel SubPix in FIG. 13, and the sensor connecting line
102 is also disposed on the right side of the subordinate light
receiving circuits 101a to 101c in FIG. 13. On the other hand, in
the even-numbered line, a display signal line 51 for transmitting a
display signal for a sub-pixel SubPix is disposed on the left side
of the sub-pixel SubPix in FIG. 13, and the sensor connecting line
102 is also disposed on the left side of the subordinate light
receiving circuits 101a to 101c in FIG. 13. In other words, the
side from which the output of a sensor SSR is extracted within each
sub-pixel SubPix is a side where a switching element SW1 is
disposed, which side is either the left side or the right side of
the sub-pixel SubPix in FIG. 13. Thus, the arrangement of the
subordinate light receiving circuit 101a and the subordinate light
receiving circuit 101c in the odd-numbered line in FIG. 13 is
opposite to the arrangement of the subordinate light receiving
circuit 101a and the subordinate light receiving circuit 101c in
the even-numbered line in FIG. 13.
FIG. 14 shows another example of arrangement of a light receiving
circuit 101. That is, FIG. 14 shows an example of arrangement of a
light receiving circuit 101 in a case where the light receiving
circuit 101 includes a subordinate light receiving circuit 101a,
four subordinate light receiving circuits 101b, and a subordinate
light receiving circuit 101c, and the subordinate light receiving
circuit 101a, the four subordinate light receiving circuits 101b,
and the subordinate light receiving circuit 101c are disposed in
six sub-pixels SubPix, respectively.
The arrangement in FIG. 14 is the same as in FIG. 13 except for a
different number of subordinate light receiving circuits 101b
(which number is also the number of sub-pixels SubPix) inserted
between the subordinate light receiving circuit 101a and the
subordinate light receiving circuit 101c.
Thus, by only changing the number of subordinate light receiving
circuits 101b inserted between the subordinate light receiving
circuit 101a and the subordinate light receiving circuit 10c, it is
possible to easily increase effective sensor size and thus improve
the S/N ratio of a received light signal.
A light receiving process by the light receiving circuit 101 will
be described with reference to a flowchart of FIG. 15.
When a reset control signal for turning off the connection of the
switching element SW2 of the light receiving circuit 101 is
supplied to the switching element SW2 of the light receiving
circuit 101, in step S1, the switching element SW2 turns off the
connection thereof to reset a received light signal.
In step S2, the respective sensors SSR of the subordinate light
receiving circuits 101a to 101c forming the light receiving circuit
101 output a current signal corresponding to an amount of light
received to the amplifier AMP.
When a readout control signal for turning on the connection of the
switching element SW3 of the light receiving circuit 101 is
supplied to the switching element SW3 of the light receiving
circuit 101, in step S3, the light receiving circuit 101 outputs a
received light signal. That is, the amplifier AMP in the
subordinate light receiving circuit 101c converts the current
signal input to the amplifier AMP into a voltage signal, and
outputs a result of amplifying the voltage signal as the received
light signal.
As described above, in the display panel 25 in which pixels are
arranged in the delta arrangement, sensors SSR respectively
disposed in a plurality of sub-pixels SubPix arranged in a
direction perpendicular to the wiring direction of the display
signal lines 51 (horizontal direction) are connected in parallel
with each other on the substrate. It is thereby possible to
effectively increase the sensor size, and thus improve the S/N
ratio of the received light signal. That is, the S/N ratio of the
received light signal can be increased with a simple
configuration.
It is to be noted that embodiments are not limited to the
above-described embodiments, and that various changes can be made
without departing from the spirit of the present application.
It should be understood that various changes and modifications to
the presently preferred embodiments described herein will be
apparent to those skilled in the art. Such changes and
modifications can be made without departing from the spirit and
scope of the present subject matter and without diminishing its
intended advantages. It is therefore intended that such changes and
modifications be covered by the appended claims.
* * * * *